The invention relates to a tensioning device for a traction mechanism, in particular, a belt or a chain, comprising a tensioning lever over which the traction mechanism is guided and on which a tensioning spring is arranged with one of its ends, wherein its other end is arranged on a spring holder by which the tensioning device can be fastened to an external object.
One such tensioning device is known, for example, from DE 195 01 685 C1. So that the assembly of this tensioning device is simplified, the tensioning device described there has a connection element that can be set in tension in the form of a spring strip extending from the spring holder to the tensioning lever, wherein a tensioning spring is provided between both in a known way. With the lower end, the spring strip is fixed on the spring holder by a pin inserted into an insertion borehole. The spring strip passes through the tensioning spring in its interior and is guided through a spring support provided on the tensioning lever on which the tensioning spring is supported with its other end. At this position on the end of the spring strip, there is another pin passing through transversely whose end is rotated by 90° about the longitudinal axis of the strip, so that a stop is produced. In the assembled position, the upper pin is inserted and supported on the tensioning lever. Because the length of the spring strip is shorter than the length of the unloaded tensioning spring, this can be fixed in the pretensioned position due to the two-sided pin support of the spring strip.
Now if the tensioning device is installed, then the upper pin is removed, so that the tensioning spring can be unloaded. Then, in addition to the pretensioning function, limiting the movement of the tensioning spring path is added to the spring strip as a second function. This is because the tensioning spring can be unloaded only as much as the spring strip stop at the end permits. Namely, if this spring runs against the tensioning lever, then the spring path is limited.
A disadvantage in this configuration is that the sheet strip is relatively thin, so that it can break after multiple forceful load applications, that is, when the spring strip runs against the stop. In addition, a spring strip that is very unstable can vibrate during use, which might lead to the generation of noise.